Contact damage of human dental enamel under cyclic axial loading with abrasive particles

The damage to human dental enamel under cyclic, axial contacts in a silica particle medium is investigated. It is found that such damage is hierarchical, affecting different length-scales of the enamel structure. At the contact surface, it consists of micron-sized defects, with an attendant increase of surface roughness due to microindentation of the abrasive particles. Below the surface, demineralization of the enamel is observed, which is attributable to inelastic processes at the nanoscale. Axial-only contacts in particulate media result in negligible wear at the macroscopic scale, but may degrade the fracture strength. Potential implications of these results in the fields of dentistry and biology are discussed.